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R33 GTR LS2 Coil Woes

07-10-2018, 11:44 AM

The old guard of GTR Canada know me, but perhaps many of us here are new and might not know the good ol' days when this forum was an integral part of a Skyline owner's life in Canada. It seems that FB killed this forum but here I am again....is this place on again? I hope so.

I have a 1995 R33 GTR with Nistune ECU and I am running LS2 coils on it. I am making this thread both for information sharing, AND for asking questions about the ignition coil setups that we can have. Around 3 years ago, I ditched my stock coil set up and switched to LS2 coils. Everything seemed to work fine, but I started noticing rougher idle and loss of power after the car was warm. With higher temperatures, it got even worse. I ended up frying one cylinder due to a Japanese piggyback system messing AFRs up, and then moved to Calgary, where Boost Factory installed a replacement engine that I had bought.

Still running the LS2 coils, I switched the ECU to Nistune, only to find that Nistune does not have the capability to control the dwell time, and no matter how much the tuner tried to play around with it, the engine continued to misfire during the tune. My setup at that time was basically stock, with 550cc injectors. The car made 285whp and 255 ft-lb of torque at 11.5 psi, with stock turbos. And this was up from 155 whp that it was making when I brought it into the shop (AutoDream). The way to counter misfire was to reduce the plug gap to around 0.6mm. However, at that small a gap, the idle got rough and the fuel consumption went through the roof.

I then swapped out the turbos with ball bearing R34 VSpec ones, which actually resulted in the car being more responsive and perhaps started to push over 310 whp. And this is where it sits right now. I want to ask others who either have experience with LS2 coils, or have other setups, as to what my options are.

My car starts fine and idles smooth when cold, with AFRs hovering between 13-14. But after it has been driven for a while and the engine is fully hot, the idle starts to get rough. There is not much drop in power, but the fuel consumption is pretty bad when cruising....the AFRs are between 11-13 when under partial throttle. And the more I drive the car, the rougher the idle gets. I have tested the coils and they are all firing, but I also feel that maybe at such a small gap, and the dwell times being what they are, these coils are not giving me the juice that they are capable of giving. Does anyone know what I can do to test them and see if there are any weak coils on my engine?

The plug wires are low resistance, MSD superconductors, so they are not the issue. I have also ruled out the possibility of bad plugs, as when I decided to run the car with 0.8mm gap, it started to misfire. You would think that a stronger coil like the LS2 would produce a stronger spark compared to the stock coils, but that's not the case. The internet is full of contradictory information on these coils, where some say that they randomly discharge, while others say that they need at least 5 ms dwell time. Also, there is no consensus on what the stock Nissan ECU dwell time is...is it 3 ms or 2.5 or 3.5?

Finally, if this setup is not going to work for me, what other economical options do I have?

Thank you all.

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